1. Field of the Invention
The present invention relates to the field of manufacture of liquid crystal display device, and in particular to a method for manufacturing a liquid crystal display device and a liquid crystal display device.
2. The Related Arts
Liquid crystal display (LCD) has a variety of advantages, such as thin device body, low power consumption, and being free of radiation, and is thus widely used. Most of the LCDs that are currently available in the market are backlighting LCDs, which comprise a liquid crystal display panel and a backlight module. The working principle of the liquid crystal display panel is that liquid crystal polymer molecules interposed between two parallel glass substrates and a plurality of vertical and horizontal fine electrical wires is arranged between the two glass substrates, whereby the liquid crystal molecules are controlled to change direction by application of electricity in order to refract light emitting from the backlight module for generating images.
Referring to FIG. 1, a liquid crystal display device is generally composed of an upper structure 100 of color filter (CF), a lower substrate 200 of thin film transistor (TFT), and liquid crystal (LC) 300, spacers 400, and sealant 500 interposed between the upper substrate 100 and the lower substrate 200. A general manufacturing process comprises a front stage of array process (including thin film, yellow light, etching, and film stripping), an intermediate stage of cell process (including bonding of TFT substrate and the CF substrate), and a rear stage of assembling process (including mounting of drive ICs and printed circuit board). The front stage of array process generally manufactures the TFT substrate in order to control the movement of liquid crystal molecules. The intermediate stage of cell process generally introduces liquid crystal between the TFT substrate and the CF substrate. The rear stage of assembling process generally mounts the drive ICs and combining the printed circuit board to effect driving the liquid crystal molecules to rotate for displaying images.
The process of introducing liquid crystal between the TFT substrate and the CF substrate is generally a process referred to as one drop filling (ODF), which generally comprises several steps of coating resin frame, filling liquid crystal, vacuum assembling, and high temperature curing. The step of filling liquid crystal is generally carried out with a distribution process or a vacuum filling method.
In the vacuum filling process, an enclosing resin frame that has an entry opening is formed between the TFT substrate and the CF substrate. The TFT substrate and the CF substrate are first bonded together and then liquid crystal is filled between the TFT substrate and the CF substrate through the entry opening of the enclosing resin frame. However, with the increase of the size of the liquid crystal display device, the vacuum filling process takes more and more time to complete. The severely affects the manufacture performance.
In the distribution method, an enclosing mold frame that has no entry opening is formed between the TFT substrate and the CF substrate. The liquid crystal is first filled inside the enclosing resin frame and then the TFT substrate and the CF substrate are bonded to each other. It is, however, generally difficult to control the amount of liquid crystal filled in the process of filling liquid crystal with the distribution method. When the liquid crystal is over-filled (as shown in FIG. 2), deformation of the TFT substrate 200 and the CF substrate 100 may result due to thermal expansion. This will cause abnormal conditions of for example inhomogeneous displaying color.